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Ios 使用Swift发送Segue数据_Ios_Swift_Segue - Fatal编程技术网
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  • ios/
  • Ios 使用Swift发送Segue数据

Ios 使用Swift发送Segue数据

ios swift

Ios 使用Swift发送Segue数据,ios,swift,segue,Ios,Swift,Segue,我有两个视图控制器和两个视图。 在我的第一个视图中，我将变量“currentUser”设置为false。 我需要能够在第二个视图控制器中将“currentUser”设置为true 当尝试从第二个视图引用“currentUser”时，它不会拾取它，因为“currentUser”是在第一个视图控制器中定义的 如何使用segue跨越变量？使用segue将任何ViewController中的值设置为第二个值 像这样： override func prepareForSegue(segue: UIStor

我有两个视图控制器和两个视图。 在我的第一个视图中，我将变量“currentUser”设置为false。 我需要能够在第二个视图控制器中将“currentUser”设置为true

当尝试从第二个视图引用“currentUser”时，它不会拾取它，因为“currentUser”是在第一个视图控制器中定义的

如何使用segue跨越变量？

使用segue将任何ViewController中的值设置为第二个值

像这样：

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {

    if(segue.identifier == "yourIdentifierInStoryboard") {

        let yourNextViewController = (segue.destinationViewController as yourNextViewControllerClass)
        yourNextViewController.value = yourValue

class CurrentUser {
    var someBooleanValue = true {
        didSet {
            print(someBooleanValue)
        }
    }
}

import UIKit

class ViewController1: UIViewController {

    let currentUser = CurrentUser()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        currentUser.someBooleanValue = false
    }
    
    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        if let viewController2 = segue.destinationViewController as? ViewController2 {
            viewController2.currentUser = currentUser
        }
    }

}

import UIKit

class ViewController2: UIViewController {

    var currentUser: CurrentUser?

    // Link this IBAction to a UIButton or a UIBarButtonItem in the Storyboard
    @IBAction func toggleBoolean(sender: AnyObject) {
        if let currentUser = currentUser {
          currentUser.someBooleanValue = !currentUser.someBooleanValue
        }
    }
    
}

import UIKit

class ViewController1: UIViewController {
    
    var currentUser = true {
        didSet {
            print(currentUser)
        }
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        currentUser = false
    }
    
    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        if let viewController2 = segue.destinationViewController as? ViewController2 {
            let closureToPerform = { [weak self] in
                if let strongSelf = self {
                    strongSelf.currentUser = !strongSelf.currentUser
                }
            }
            viewController2.closureToPerform = closureToPerform
        }
    }
    
}

import UIKit

class ViewController2: UIViewController {

    var closureToPerform: (() -> Void)?

    // Link this IBAction to a UIButton or a UIBarButtonItem in the Storyboard
    @IBAction func toggleBoolean(sender: AnyObject) {
        closureToPerform?()
    }
    
}

protocol MyDelegate: class {
    func changeValue()
}

import UIKit

class ViewController1: UIViewController, MyDelegate {

    var currentUser = true {
        didSet {
            print(currentUser)
        }
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        currentUser = false
    }
    
    func changeValue() {
        currentUser = !currentUser
    }
    
    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        if let viewController2 = segue.destinationViewController as? ViewController2 {
            viewController2.delegate = self
        }
    }

}

import UIKit
    
class ViewController2: UIViewController {

    weak var delegate: MyDelegate?

    // Link this IBAction to a UIButton or a UIBarButtonItem in the Storyboard
    @IBAction func toggleBoolean(sender: AnyObject) {
        delegate?.changeValue()
    }
    
}
在您的下一个YourtViewController类中

class yourNextViewControllerClass {

    var value:Int! // or whatever
您也可以通过编程方式调用它：

 self.performSegueWithIdentifier("yourIdentifierInStoryboard", sender: self)
将值从DestinationViewController设置回主（第一个）ViewController

1。实施协议，例如创建名为protocol.swift的文件

    protocol changeUserValueDelegate {
       func changeUser(toValue:Bool)
    }
2.在第二个视图上设置代理

    class yourNextViewControllerClass {

    var delegate:changeUserValueDelegate?
3.设置加载的代理（prepareForSegue）

4.向FirstViewController添加功能

    func changeUser(toValue:Bool) {
        self.currentUserValue = toValue
    }

     delegate?.changeUser(true)

    class FirstViewController: UIViewController, ChangeUserValueDelegate {
5。从SecondViewController调用此函数

    func changeUser(toValue:Bool) {
        self.currentUserValue = toValue
    }

     delegate?.changeUser(true)

    class FirstViewController: UIViewController, ChangeUserValueDelegate {
6.在FirstViewController中设置代理

    func changeUser(toValue:Bool) {
        self.currentUserValue = toValue
    }

     delegate?.changeUser(true)

    class FirstViewController: UIViewController, ChangeUserValueDelegate {
在目标视图控制器中添加属性
currentUserSecondVC
，并使用
prepareforsgue

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
    if segue.identifier == "Name Of Your Segue" {
        var vc = segue.destinationViewController as NameOfTheSecondViewController
        vc.currentUserSecondVC = !currentUser //you can do whatever you want with it in the 2nd VC
    }
}
这里的问题是您的
currentUser
变量的类型为
Bool
，这是一种值类型。因此，将它从第一个视图控制器传递到第二个视图控制器实际上将创建一个新的
Bool
实例。您需要的是将引用从第一个视图控制器传递到第二个视图控制器（有关Swift的值和引用的更多详细信息，请参阅）

因此，根据您的需要/偏好，您可以从以下三个示例中选择一个

1.拳击风格 在这里，我们在一个类中“装箱”我们的
Bool
，并将该类实例的引用传递给第二个视图控制器

1.1。创建一个
CurrentUser
类：

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {

    if(segue.identifier == "yourIdentifierInStoryboard") {

        let yourNextViewController = (segue.destinationViewController as yourNextViewControllerClass)
        yourNextViewController.value = yourValue

class CurrentUser {
    var someBooleanValue = true {
        didSet {
            print(someBooleanValue)
        }
    }
}

import UIKit

class ViewController1: UIViewController {

    let currentUser = CurrentUser()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        currentUser.someBooleanValue = false
    }
    
    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        if let viewController2 = segue.destinationViewController as? ViewController2 {
            viewController2.currentUser = currentUser
        }
    }

}

import UIKit

class ViewController2: UIViewController {

    var currentUser: CurrentUser?

    // Link this IBAction to a UIButton or a UIBarButtonItem in the Storyboard
    @IBAction func toggleBoolean(sender: AnyObject) {
        if let currentUser = currentUser {
          currentUser.someBooleanValue = !currentUser.someBooleanValue
        }
    }
    
}

import UIKit

class ViewController1: UIViewController {
    
    var currentUser = true {
        didSet {
            print(currentUser)
        }
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        currentUser = false
    }
    
    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        if let viewController2 = segue.destinationViewController as? ViewController2 {
            let closureToPerform = { [weak self] in
                if let strongSelf = self {
                    strongSelf.currentUser = !strongSelf.currentUser
                }
            }
            viewController2.closureToPerform = closureToPerform
        }
    }
    
}

import UIKit

class ViewController2: UIViewController {

    var closureToPerform: (() -> Void)?

    // Link this IBAction to a UIButton or a UIBarButtonItem in the Storyboard
    @IBAction func toggleBoolean(sender: AnyObject) {
        closureToPerform?()
    }
    
}

protocol MyDelegate: class {
    func changeValue()
}

import UIKit

class ViewController1: UIViewController, MyDelegate {

    var currentUser = true {
        didSet {
            print(currentUser)
        }
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        currentUser = false
    }
    
    func changeValue() {
        currentUser = !currentUser
    }
    
    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        if let viewController2 = segue.destinationViewController as? ViewController2 {
            viewController2.delegate = self
        }
    }

}

import UIKit
    
class ViewController2: UIViewController {

    weak var delegate: MyDelegate?

    // Link this IBAction to a UIButton or a UIBarButtonItem in the Storyboard
    @IBAction func toggleBoolean(sender: AnyObject) {
        delegate?.changeValue()
    }
    
}
1.2。为第一个视图控制器创建
UIViewController
子类：

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {

    if(segue.identifier == "yourIdentifierInStoryboard") {

        let yourNextViewController = (segue.destinationViewController as yourNextViewControllerClass)
        yourNextViewController.value = yourValue

class CurrentUser {
    var someBooleanValue = true {
        didSet {
            print(someBooleanValue)
        }
    }
}

import UIKit

class ViewController1: UIViewController {

    let currentUser = CurrentUser()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        currentUser.someBooleanValue = false
    }
    
    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        if let viewController2 = segue.destinationViewController as? ViewController2 {
            viewController2.currentUser = currentUser
        }
    }

}

import UIKit

class ViewController2: UIViewController {

    var currentUser: CurrentUser?

    // Link this IBAction to a UIButton or a UIBarButtonItem in the Storyboard
    @IBAction func toggleBoolean(sender: AnyObject) {
        if let currentUser = currentUser {
          currentUser.someBooleanValue = !currentUser.someBooleanValue
        }
    }
    
}

import UIKit

class ViewController1: UIViewController {
    
    var currentUser = true {
        didSet {
            print(currentUser)
        }
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        currentUser = false
    }
    
    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        if let viewController2 = segue.destinationViewController as? ViewController2 {
            let closureToPerform = { [weak self] in
                if let strongSelf = self {
                    strongSelf.currentUser = !strongSelf.currentUser
                }
            }
            viewController2.closureToPerform = closureToPerform
        }
    }
    
}

import UIKit

class ViewController2: UIViewController {

    var closureToPerform: (() -> Void)?

    // Link this IBAction to a UIButton or a UIBarButtonItem in the Storyboard
    @IBAction func toggleBoolean(sender: AnyObject) {
        closureToPerform?()
    }
    
}

protocol MyDelegate: class {
    func changeValue()
}

import UIKit

class ViewController1: UIViewController, MyDelegate {

    var currentUser = true {
        didSet {
            print(currentUser)
        }
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        currentUser = false
    }
    
    func changeValue() {
        currentUser = !currentUser
    }
    
    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        if let viewController2 = segue.destinationViewController as? ViewController2 {
            viewController2.delegate = self
        }
    }

}

import UIKit
    
class ViewController2: UIViewController {

    weak var delegate: MyDelegate?

    // Link this IBAction to a UIButton or a UIBarButtonItem in the Storyboard
    @IBAction func toggleBoolean(sender: AnyObject) {
        delegate?.changeValue()
    }
    
}
1.3。为第二个视图控制器创建
UIViewController
子类：

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {

    if(segue.identifier == "yourIdentifierInStoryboard") {

        let yourNextViewController = (segue.destinationViewController as yourNextViewControllerClass)
        yourNextViewController.value = yourValue

class CurrentUser {
    var someBooleanValue = true {
        didSet {
            print(someBooleanValue)
        }
    }
}

import UIKit

class ViewController1: UIViewController {

    let currentUser = CurrentUser()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        currentUser.someBooleanValue = false
    }
    
    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        if let viewController2 = segue.destinationViewController as? ViewController2 {
            viewController2.currentUser = currentUser
        }
    }

}

import UIKit

class ViewController2: UIViewController {

    var currentUser: CurrentUser?

    // Link this IBAction to a UIButton or a UIBarButtonItem in the Storyboard
    @IBAction func toggleBoolean(sender: AnyObject) {
        if let currentUser = currentUser {
          currentUser.someBooleanValue = !currentUser.someBooleanValue
        }
    }
    
}

import UIKit

class ViewController1: UIViewController {
    
    var currentUser = true {
        didSet {
            print(currentUser)
        }
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        currentUser = false
    }
    
    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        if let viewController2 = segue.destinationViewController as? ViewController2 {
            let closureToPerform = { [weak self] in
                if let strongSelf = self {
                    strongSelf.currentUser = !strongSelf.currentUser
                }
            }
            viewController2.closureToPerform = closureToPerform
        }
    }
    
}

import UIKit

class ViewController2: UIViewController {

    var closureToPerform: (() -> Void)?

    // Link this IBAction to a UIButton or a UIBarButtonItem in the Storyboard
    @IBAction func toggleBoolean(sender: AnyObject) {
        closureToPerform?()
    }
    
}

protocol MyDelegate: class {
    func changeValue()
}

import UIKit

class ViewController1: UIViewController, MyDelegate {

    var currentUser = true {
        didSet {
            print(currentUser)
        }
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        currentUser = false
    }
    
    func changeValue() {
        currentUser = !currentUser
    }
    
    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        if let viewController2 = segue.destinationViewController as? ViewController2 {
            viewController2.delegate = self
        }
    }

}

import UIKit
    
class ViewController2: UIViewController {

    weak var delegate: MyDelegate?

    // Link this IBAction to a UIButton or a UIBarButtonItem in the Storyboard
    @IBAction func toggleBoolean(sender: AnyObject) {
        delegate?.changeValue()
    }
    
}
2.封闭式 这里，我们在闭包中获得第一个视图控制器的弱引用，并将此闭包传递给第二个视图控制器

2.1。为第一个视图控制器创建
UIViewController
子类：

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {

    if(segue.identifier == "yourIdentifierInStoryboard") {

        let yourNextViewController = (segue.destinationViewController as yourNextViewControllerClass)
        yourNextViewController.value = yourValue

class CurrentUser {
    var someBooleanValue = true {
        didSet {
            print(someBooleanValue)
        }
    }
}

import UIKit

class ViewController1: UIViewController {

    let currentUser = CurrentUser()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        currentUser.someBooleanValue = false
    }
    
    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        if let viewController2 = segue.destinationViewController as? ViewController2 {
            viewController2.currentUser = currentUser
        }
    }

}

import UIKit

class ViewController2: UIViewController {

    var currentUser: CurrentUser?

    // Link this IBAction to a UIButton or a UIBarButtonItem in the Storyboard
    @IBAction func toggleBoolean(sender: AnyObject) {
        if let currentUser = currentUser {
          currentUser.someBooleanValue = !currentUser.someBooleanValue
        }
    }
    
}

import UIKit

class ViewController1: UIViewController {
    
    var currentUser = true {
        didSet {
            print(currentUser)
        }
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        currentUser = false
    }
    
    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        if let viewController2 = segue.destinationViewController as? ViewController2 {
            let closureToPerform = { [weak self] in
                if let strongSelf = self {
                    strongSelf.currentUser = !strongSelf.currentUser
                }
            }
            viewController2.closureToPerform = closureToPerform
        }
    }
    
}

import UIKit

class ViewController2: UIViewController {

    var closureToPerform: (() -> Void)?

    // Link this IBAction to a UIButton or a UIBarButtonItem in the Storyboard
    @IBAction func toggleBoolean(sender: AnyObject) {
        closureToPerform?()
    }
    
}

protocol MyDelegate: class {
    func changeValue()
}

import UIKit

class ViewController1: UIViewController, MyDelegate {

    var currentUser = true {
        didSet {
            print(currentUser)
        }
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        currentUser = false
    }
    
    func changeValue() {
        currentUser = !currentUser
    }
    
    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        if let viewController2 = segue.destinationViewController as? ViewController2 {
            viewController2.delegate = self
        }
    }

}

import UIKit
    
class ViewController2: UIViewController {

    weak var delegate: MyDelegate?

    // Link this IBAction to a UIButton or a UIBarButtonItem in the Storyboard
    @IBAction func toggleBoolean(sender: AnyObject) {
        delegate?.changeValue()
    }
    
}
2.2。为第二个视图控制器创建
UIViewController
子类：

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {

    if(segue.identifier == "yourIdentifierInStoryboard") {

        let yourNextViewController = (segue.destinationViewController as yourNextViewControllerClass)
        yourNextViewController.value = yourValue

class CurrentUser {
    var someBooleanValue = true {
        didSet {
            print(someBooleanValue)
        }
    }
}

import UIKit

class ViewController1: UIViewController {

    let currentUser = CurrentUser()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        currentUser.someBooleanValue = false
    }
    
    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        if let viewController2 = segue.destinationViewController as? ViewController2 {
            viewController2.currentUser = currentUser
        }
    }

}

import UIKit

class ViewController2: UIViewController {

    var currentUser: CurrentUser?

    // Link this IBAction to a UIButton or a UIBarButtonItem in the Storyboard
    @IBAction func toggleBoolean(sender: AnyObject) {
        if let currentUser = currentUser {
          currentUser.someBooleanValue = !currentUser.someBooleanValue
        }
    }
    
}

import UIKit

class ViewController1: UIViewController {
    
    var currentUser = true {
        didSet {
            print(currentUser)
        }
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        currentUser = false
    }
    
    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        if let viewController2 = segue.destinationViewController as? ViewController2 {
            let closureToPerform = { [weak self] in
                if let strongSelf = self {
                    strongSelf.currentUser = !strongSelf.currentUser
                }
            }
            viewController2.closureToPerform = closureToPerform
        }
    }
    
}

import UIKit

class ViewController2: UIViewController {

    var closureToPerform: (() -> Void)?

    // Link this IBAction to a UIButton or a UIBarButtonItem in the Storyboard
    @IBAction func toggleBoolean(sender: AnyObject) {
        closureToPerform?()
    }
    
}

protocol MyDelegate: class {
    func changeValue()
}

import UIKit

class ViewController1: UIViewController, MyDelegate {

    var currentUser = true {
        didSet {
            print(currentUser)
        }
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        currentUser = false
    }
    
    func changeValue() {
        currentUser = !currentUser
    }
    
    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        if let viewController2 = segue.destinationViewController as? ViewController2 {
            viewController2.delegate = self
        }
    }

}

import UIKit
    
class ViewController2: UIViewController {

    weak var delegate: MyDelegate?

    // Link this IBAction to a UIButton or a UIBarButtonItem in the Storyboard
    @IBAction func toggleBoolean(sender: AnyObject) {
        delegate?.changeValue()
    }
    
}
3.协议委托样式 这里，我们使第一个视图控制器符合某种协议，并将其弱引用传递给第二个视图控制器

3.1。创建自定义协议：

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {

    if(segue.identifier == "yourIdentifierInStoryboard") {

        let yourNextViewController = (segue.destinationViewController as yourNextViewControllerClass)
        yourNextViewController.value = yourValue

class CurrentUser {
    var someBooleanValue = true {
        didSet {
            print(someBooleanValue)
        }
    }
}

import UIKit

class ViewController1: UIViewController {

    let currentUser = CurrentUser()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        currentUser.someBooleanValue = false
    }
    
    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        if let viewController2 = segue.destinationViewController as? ViewController2 {
            viewController2.currentUser = currentUser
        }
    }

}

import UIKit

class ViewController2: UIViewController {

    var currentUser: CurrentUser?

    // Link this IBAction to a UIButton or a UIBarButtonItem in the Storyboard
    @IBAction func toggleBoolean(sender: AnyObject) {
        if let currentUser = currentUser {
          currentUser.someBooleanValue = !currentUser.someBooleanValue
        }
    }
    
}

import UIKit

class ViewController1: UIViewController {
    
    var currentUser = true {
        didSet {
            print(currentUser)
        }
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        currentUser = false
    }
    
    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        if let viewController2 = segue.destinationViewController as? ViewController2 {
            let closureToPerform = { [weak self] in
                if let strongSelf = self {
                    strongSelf.currentUser = !strongSelf.currentUser
                }
            }
            viewController2.closureToPerform = closureToPerform
        }
    }
    
}

import UIKit

class ViewController2: UIViewController {

    var closureToPerform: (() -> Void)?

    // Link this IBAction to a UIButton or a UIBarButtonItem in the Storyboard
    @IBAction func toggleBoolean(sender: AnyObject) {
        closureToPerform?()
    }
    
}

protocol MyDelegate: class {
    func changeValue()
}

import UIKit

class ViewController1: UIViewController, MyDelegate {

    var currentUser = true {
        didSet {
            print(currentUser)
        }
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        currentUser = false
    }
    
    func changeValue() {
        currentUser = !currentUser
    }
    
    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        if let viewController2 = segue.destinationViewController as? ViewController2 {
            viewController2.delegate = self
        }
    }

}

import UIKit
    
class ViewController2: UIViewController {

    weak var delegate: MyDelegate?

    // Link this IBAction to a UIButton or a UIBarButtonItem in the Storyboard
    @IBAction func toggleBoolean(sender: AnyObject) {
        delegate?.changeValue()
    }
    
}
3.2。为第一个视图控制器创建一个
UIViewController
子类，并使其符合前面的协议：

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {

    if(segue.identifier == "yourIdentifierInStoryboard") {

        let yourNextViewController = (segue.destinationViewController as yourNextViewControllerClass)
        yourNextViewController.value = yourValue

class CurrentUser {
    var someBooleanValue = true {
        didSet {
            print(someBooleanValue)
        }
    }
}

import UIKit

class ViewController1: UIViewController {

    let currentUser = CurrentUser()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        currentUser.someBooleanValue = false
    }
    
    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        if let viewController2 = segue.destinationViewController as? ViewController2 {
            viewController2.currentUser = currentUser
        }
    }

}

import UIKit

class ViewController2: UIViewController {

    var currentUser: CurrentUser?

    // Link this IBAction to a UIButton or a UIBarButtonItem in the Storyboard
    @IBAction func toggleBoolean(sender: AnyObject) {
        if let currentUser = currentUser {
          currentUser.someBooleanValue = !currentUser.someBooleanValue
        }
    }
    
}

import UIKit

class ViewController1: UIViewController {
    
    var currentUser = true {
        didSet {
            print(currentUser)
        }
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        currentUser = false
    }
    
    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        if let viewController2 = segue.destinationViewController as? ViewController2 {
            let closureToPerform = { [weak self] in
                if let strongSelf = self {
                    strongSelf.currentUser = !strongSelf.currentUser
                }
            }
            viewController2.closureToPerform = closureToPerform
        }
    }
    
}

import UIKit

class ViewController2: UIViewController {

    var closureToPerform: (() -> Void)?

    // Link this IBAction to a UIButton or a UIBarButtonItem in the Storyboard
    @IBAction func toggleBoolean(sender: AnyObject) {
        closureToPerform?()
    }
    
}

protocol MyDelegate: class {
    func changeValue()
}

import UIKit

class ViewController1: UIViewController, MyDelegate {

    var currentUser = true {
        didSet {
            print(currentUser)
        }
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        currentUser = false
    }
    
    func changeValue() {
        currentUser = !currentUser
    }
    
    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        if let viewController2 = segue.destinationViewController as? ViewController2 {
            viewController2.delegate = self
        }
    }

}

import UIKit
    
class ViewController2: UIViewController {

    weak var delegate: MyDelegate?

    // Link this IBAction to a UIButton or a UIBarButtonItem in the Storyboard
    @IBAction func toggleBoolean(sender: AnyObject) {
        delegate?.changeValue()
    }
    
}
3.3。为第二个视图控制器创建
UIViewController
子类：

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {

    if(segue.identifier == "yourIdentifierInStoryboard") {

        let yourNextViewController = (segue.destinationViewController as yourNextViewControllerClass)
        yourNextViewController.value = yourValue

class CurrentUser {
    var someBooleanValue = true {
        didSet {
            print(someBooleanValue)
        }
    }
}

import UIKit

class ViewController1: UIViewController {

    let currentUser = CurrentUser()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        currentUser.someBooleanValue = false
    }
    
    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        if let viewController2 = segue.destinationViewController as? ViewController2 {
            viewController2.currentUser = currentUser
        }
    }

}

import UIKit

class ViewController2: UIViewController {

    var currentUser: CurrentUser?

    // Link this IBAction to a UIButton or a UIBarButtonItem in the Storyboard
    @IBAction func toggleBoolean(sender: AnyObject) {
        if let currentUser = currentUser {
          currentUser.someBooleanValue = !currentUser.someBooleanValue
        }
    }
    
}

import UIKit

class ViewController1: UIViewController {
    
    var currentUser = true {
        didSet {
            print(currentUser)
        }
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        currentUser = false
    }
    
    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        if let viewController2 = segue.destinationViewController as? ViewController2 {
            let closureToPerform = { [weak self] in
                if let strongSelf = self {
                    strongSelf.currentUser = !strongSelf.currentUser
                }
            }
            viewController2.closureToPerform = closureToPerform
        }
    }
    
}

import UIKit

class ViewController2: UIViewController {

    var closureToPerform: (() -> Void)?

    // Link this IBAction to a UIButton or a UIBarButtonItem in the Storyboard
    @IBAction func toggleBoolean(sender: AnyObject) {
        closureToPerform?()
    }
    
}

protocol MyDelegate: class {
    func changeValue()
}

import UIKit

class ViewController1: UIViewController, MyDelegate {

    var currentUser = true {
        didSet {
            print(currentUser)
        }
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        currentUser = false
    }
    
    func changeValue() {
        currentUser = !currentUser
    }
    
    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        if let viewController2 = segue.destinationViewController as? ViewController2 {
            viewController2.delegate = self
        }
    }

}

import UIKit
    
class ViewController2: UIViewController {

    weak var delegate: MyDelegate?

    // Link this IBAction to a UIButton or a UIBarButtonItem in the Storyboard
    @IBAction func toggleBoolean(sender: AnyObject) {
        delegate?.changeValue()
    }
    
}
应定义为覆盖的功能为：

open func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    if (segue.identifier == "Segue Name Defined In Storyboard") {
        //set the property of the designated view controller with the value you need
    }
}
因为您在两个ViewController中使用相同的变量，即currentUser（类型Bool）

因此，最好在这两个类中都将其设置为全局变量

当谈到swift中的全局变量概念时。

默认情况下，swift中的所有内容都是公共的，因此，如果您声明如下内容：

class FirstViewController: UIViewController {

    var someVariable: Boll = YES

    init(nibName nibNameOrNil: String?, bundle nibBundleOrNil: NSBundle?) {
        super.init(nibName: nibNameOrNil, bundle: nibBundleOrNil)
    }
}
只要有实例，就可以访问它并设置值：

var MySecondViewController: FirstViewController = FirstViewController(nibName: nil, bundle: nil)
var getThatValue = MySecondViewController.someVariable
据我所知，我不能使用函数，我需要在“if”语句中这样做。很抱歉没有说得更清楚。使用这两种方法，您可以将数据从第一视图控制器发送到第二视图控制器，并从第二视图控制器发送到第一视图控制器。在“if”语句中调用它应该没有问题。我尝试了第一种方法，在if语句中无法使用覆盖函数，在第二个视图控制器中找不到变量。非常好的解决方案。在找到这个之前，我一直在寻找返回firstViewController的方法。另一个好处是，我现在已经编写并使用了我的第一个自主开发的协议！在理解控制器间协议通信的这种变体时带来的启示，谢谢。